As a small-sized information memory apparatus which can record information highly densely, a scanning probe memory apparatus is listed.
The recording/reproducing principle of the scanning probe memory apparatus has various types: using a tunnel effect, using an atomic force, using a magnetic force, using an electrostatic force, using a non-linear dielectric constant, and using heat deformation of a recording medium.
The scanning probe memory apparatus is normally provided with: a probe having a tip with a radius of about several tens nanometers to several micrometers; and a plate-like (or flat) recording medium having a recording surface formed on its surface. The scanning probe memory apparatus brings the tip of the probe closer to or into contact with the recording surface of the recording medium, to thereby perform information recording or reading on the recording medium.
Moreover, the scanning probe memory apparatus displaces the probe or the recording medium in a parallel direction to the recording surface, to thereby change the position between the probe and the recording medium. By this, it is possible to scan the recording surface of the recording medium, using the probe, so that a large amount of information can be arranged on the recording surface, highly densely. Alternatively, the large amount of information arranged on the recording surface can be read, continuously or randomly. For such displacement of the probe or the recording medium, an electromagnetically-driven or electrostatically-driven actuator using e.g. a MEMS (Micro Electro Mechanical System) technology is used.
Moreover, most scanning probe memory apparatuses adopt a multi-probe method. That is, most scanning probe memory apparatuses are provided with: a two-dimensional probe head in which several tens, or several hundreds, or several thousands of probes are arranged in a matrix, for example. By using such a probe head, it is possible to quickly record the large amount of information into the recording medium, or it is possible to quickly read the large amount of information from the recording medium.